Electric tool



Dec. 6, 1927.

C. S. WEYANDT ELECTRIC TOOL Original Filed July 26, 1922 l .1 10. 100.1101 10.01 10Q 1 .900H0N0NM000N0N000000 0000 0 0 0000000000000000 000000 000000 00 0 000o0000000000000000000000000000 0.000, 00N0N000000000000 0 0 Patented Dec. 6, 1927.

UNITED STATES oFFIcE.

GARL S. WEYANDT, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO CENTRAL ELEC-TRIO TOOL COMPANY, 0F PITTSBURGH, PENNSYLVANIA, A CORPORATION OFPENNSYLVANIA.

ELECTRIC TOOL.

Application led July 2G, 1922, Serial No. 577,720. Renewed J'une 8,1926.

My invention relates to electric tools of the hammer class where anelectromagnetically operated armature is caused to vibrate orreciprocate and operate a hammer, riveter, drill, chisel, or the like.

It is the object of the present invention to provide a tool' of theclass mentioned which is compact, readily assembled and taken apart,well sealed against the admission of moisture to the windings and otherinterior parts, comparativelyl simple in construction, and reliable andeiiicient in use.

' Referring to the accompanying drawing, Fig. 1 is a centrallongitudinal section of my improved tool in its preferred form, and Fig.2, a cross-section on the line 1lb-T11 of Fig. 1.

On the drawings, 2 designates a non-.magnetic cylinder or barrel inwhich the magnetic core, armature, or striking element l isreciprocable. rlhe barrel has at one end the external threads 4 and atthe other end the internal threads 5, and is surrounded by twoelectromagnets 6 and 7 which have the respective windings 37 and 38 andwhose magnetic circuits are separated by the libre washer 8. rlhemagnets have their magnetic circuits composed partly of the. steelcasing` 9 and partly of L-shaped laminated steel field members v10arranged radially .around the barrel. Each member 10 has a radial arm 11lying against an end of a winding and an arm 12 dying parallel with thebarrel between the latter and a winding. Each magnet has two annularseries of field members with the free ends of the arms 12 of one seriesfacing or opposite the correspending ends of the other series, providingair gaps wholly within the windings. rfhese ends are beveled and havelugs or extensions 13 in slots in the barrel 2. 'lhe outer ends of thearms 11 engage the casing 9 of magnetizable material.

14 is a ca i screwing on the threads 4 and having the liange 15 whichbears against a fibre washer 16 imbedded in the inner wall 17 of theopening 18 in the handle 19. A. short fibre rin Y 20 lies between thecap and the handle an abuts against the washer 16. A fibre washer 21abuts against the inner end of the handle and the ring 20 surround' ingthe cap, and bears against the inner end of the casing 9. A fibre washer22 lies between the cap and the casing, and also between the washer 21and the arms 11nearest the handle.

The handle end of the barrel contains the reciprocable hollow core-stop23 having its outer end closed and having the flange 24 working in theenlarged'portion 25 of the barrel and limited in its inner movements bythe shoulder 26 and in its outer movements by the coiled spring 27between the closed ends of the cap and core-stop. 28 is a set-screwthreaded'in the handle and engaging the cap' 14 to prevent theaccidental loosening of the cap.

29 is a non-magnetic nose piece or cap which engages the outer end ofthe casing 9, surrounds the outer end of the barrel, and has a flange 30abutting against the said end of the barrel. A steel tool bushin 31extends through the cap 29.. screws vinto the threads 5, and has theflange 32 which engages the washer 33 on the end of the cap 29.

34 is a tool, such as a riveting tool, or a drill, having the shank 35slidable in the tool bushing 31, the tool having a shoulder 36 adapte toengage the bushing when the tool is in its innermost position, as shownin Fig. 1. "When in this position the end of the shankprojects beyondthe inner end of the bushing and lies about opposite the outer circle oflugs 13, preferably about as shown in Fig. 1.. course, good results maybe had if the end of the tool is not placed precisely as shown.

The end surfaces of the tool shank 35 and of the core stop 23 should beso disposed, relative to the air gaps between the lugs or tenons 13,that one end of the core 1 will project into one air gap when the otherend of the core is at its extreme operating position adjacent the otherair gap. rlhus, when the core engages the tool shank, its rear endsurface should be adjacent the air gap of rear solenoid 6. When the coreengages the core stop, its front end surface should be adjacent thefront air gap of solenoid 7.' rlthe core l in its forward and backwardAInovements closes each air gap or reduf. es each air gap to minimumlength, and continues be yond the yposition of minimum air gap length.

The parts being assembled as described and shown, they may be veryclosely drawnv left end of the core and the extensions 13? of the lefthand eld members 10. This pulls the core to the left and causes it tostrike the shank 35 of the tool 34.' The winding 38 nowr becomesde-energized and the winding 37 is energized by another alternation orpulsation of current, which causes aflux to be generated to pull thecore to the lright and against the core-stop 24, whereupon the secondcycle of operation begins causing the core to moveto the left and to theright as before.4 These cycles continue as long as current is fedalternately to the windings in the manner described.

When a tool is not disposed in the hammer, and the core occupies itsextreme t'orward position' against the tool bushing 31, the rear end ofthe core will bevforward of and out of the rear air gap or fiux region,and the core cannot then be moved 'by the rear solenoid 6.- If thehammer is held vertically while the vtool is out, the core will assumeits extreme forward or lowermost position and will notl respond to theflux of the retrieving coil 6. This is an important and desirablefeature since reciprocation of the core while the tool is not inposition would impress severe stresses upon the tool socketiand tend toshear the threads 5 of the ba'rrel. Damage to the hammer structure isthus precluded, however, if the operating switch be inadvertently closedwhile the tool is not in operating position, since the solenoid 6.-willnot actuate the core.

By having the inner ends 'of the eld members project into openings inthe barrel close to the core 1, in its dierent positions, the shortestpossible transverse air-gapsare provided. I prefer to make the windings`with a central internal annulus itting between the opposed ends of thearms 12 so that the flux density between the said opposed ends andthrough the core and the gaps at its ends is increased.

Certain features disclosed in this application, including, lamongothers, the construction and disposition of the magnetic field membersor laminations, and the rooperative relation of a movable coretherewith, are claimed broadly in my co-pending application for areciprocating electric motor, Serial No. 697,053, led March 5, 1924, acontinuation of application Serial No. 527,037, tiled Jan. et, 1922; andcertain other features disclosed herein, particularly the doublesolenoid field structure broadly, is claimed in my co-pendingapplication Serial No. 541,517, liled ll/Iarch 6, 1922.

I claim- 1. In an electric tool, a non-magnetic barrel, a tool shank atone end of the barrel, a core-stop at the other end thereof, two axiallyalined windings surrounding the barrel, magnetic field members arrangedaround the barrel and within the windings, the lield members beinginterrupted to form short air-gaps Within the length of each winding,and a magnetic core reciprocable in the barrel and having its endsarranged to be drawn into the air-gaps alternately by by alternateenergization of the windings.

2. In an electric tool, a non-magnetic barrel, a tool-shank at on'e endof the barrel, a core-stop at the other end thereof, two axiallyl alinedwindings surrounding the barrel, magnetic field members arranged aroundthe barrel and Within the windings, the tield members being interruptedto form short air-gaps within the length of each winding, and a magneticcore reciprocable in the barrel and having its ends arranged to be drawnenergization of the windings, theA magnetic members extending throughthe barrel-wall at the ends of the air-gaps.

3. In an electric tool, a non-magnetic barrel, a tool-shank at one endof the barrel, a core-stop at the other end thereof, two axially alinedwindings surrounding the barrel` Vmagnetic field members arranged aroundthe barrel and within the windings, the field members being interruptedto form air-gaps within the length of each winding, and a magnetic corereciprocable in the barrel and havino its ends arranged to be drawn intothe air-gaps alternately by alternate energization of the windings, themagnetic members .extending through the barrel-wall at the ends of theair-gaps and the windings having each an internal annulus in theadjacent air-gap.

4. In an electric tool, anon-magnetic barrel, a tool-shank projectinginto one end of the barrel, and a core-stop projecting into the otherend thereof, two axially alined windings surrounding the barrel,radiallyarranged field members, having radial arms at the ends of thewindings and other arms lying between the windings and the barrel. theends of the second arms for each winding being spaced apart Within thelength of the windingmeans for completing the magnetic circuits betweenthe 'ends of the radialI -into the air-gaps alternately by alternate Yarms, and a magnetic core reciprocable in the barrel between thetool-shank and the core-stop. A

5. In an electric tool, a non-magnetic barf. rel,'a tool-shankprojecting into one end of the barrel, and a core-stop projecting intothe other end thereof, two axially alined f windings surrounding thebarrel, radiallyhave its ends magnetically drawn alternately into thesaid air-gaps.

6. In an electric tool, a non-magnetic barrel, a tool-shank projectinginto one end of the barrel, and a core-stop projecting into the otherend thereof, two axially alined windings surrounding the barrel, meansproviding magnetic circuits for the windings having air-gaps between theends ofthe windings and wholly within the latter, and :i magnetic corehaving its ends arranged to be drawn into air-gaps of' the respectivemagnetic circuits from each end of its stroke.

7, In an electric tool, a non-magnetic barrel, a lmagnetic corereciprocable therein, a reciprocable core-stop in one end of 'thebarrel, two axially-alined electro-magnets surrounding the barrel,laminated magnetic circuit members associated with each electromagnetand disposed radially around the barrel, a easing surrounding themagnets and fitting tightly over the laminated members to complete themagnetic circuits, a nose-piece closing one end of the casing, atool-bushingextending through the nose piece and into the barrel, andclamping the nose-piece to the barrel, a tool-shank in the bushing andprojecting into the barrel and into the path of the core, a closure forthe remaining end of the casing, and means adjustably connected to thebarrel for forcing the closures tightly against the endsof the casingand unit-ing the described parts into a rigid unit 8. In an electrictool, a non-magnetic barrel, a magnetic core reciprocable therein, areciprocable core-stop in one end of the barrel, two axially-aimedelectro-magnets surrounding the barrel. laminated magnetic circuitmembers therefor radially disposed around the barrel a casingsurrounding the magnets and serving to complete the magnetic circuitbetween the laminated members, a nose-piece closing one end of thecasthe nose-piece to the barrel, a tool-shank in the bushing andprojecting into the barrel and into the path of the core, a closure forthe remaining end of the casing, and a cap screwing on the barrel andhaving a fiange working on the outer face of the second closure to clampthev described parts into a rigid unit.

9. In an electric tool, a. non-magnetic barrel, a magnetic corereciprocable therein, a reciprocable core-stop in one end of the barrel,two axially-alined electro-magnets surrounding the barrel, magneticcircuit members radially disposed around the barrel and serving to holdthe magnets in place, a casing surrounding the magnets and tightlyfitting the magnetic members to complete magnetic circuits therebetween,a nose-piece closing one end of the casing, a tool-bushing extendingthrough the nose-piece and into the barrel, and clamping the nose-pieceto the barrel, a tool-shank in the bushing and projecting into thebarrel and into the path of the core, a closure for the remaining end ofthe casing. a cap screwing on the barrel and having a flange working onthe outer face of the second closure to clamp the described parts into arigid unit, and a spring to urge the core-stop toward the. core and heldunder tension by the cap.

10. In an electric tool, the combination with a winding, of an innershell built up of' laminations to constitute a portion of the magneticcircuit for the winding and an outer shell serving as a casing for thetool and as a portion of the magnetic circuit for the winding.

11. In an electric hammer, the combination with a movable core memberand an actuating coil therefor, of a plurality of' members constitutingthe internal magnetic circuit conductor and an enclosing tubeconstiltuting the external magnetic circuit conductor, said, core havingsuch characteristics and being so slitted as to provide paths ofrelatively high resistance to electric currents and relatively lowreluctance to magnetic flux.

l2. An electric tool of the reciprocating motor type comprising a barrelprovided with an enlarged flange-like portion at each. end constitutinga shoulder onI the barrel, one portion being externally threaded and theother end of the barrel being internally threaded, magnetic fieldmembers seated on the barrel. and snugly held in osition against saidshoulders by tenons fitting into the barrel, solenoids associated withsaid magnetic field members, a core responsive thereto, a casing fittingover the field members and enclosing Ithe solenoids, a nose piecefitting over one end of the barrel against the field members, a toolsocket for clamping the nose piece to the barrel, a bumper in the btherend of the barrel, a handle piece fit- "ting over the same end of thebarrel to noids in position and locking portions fitting into thebarrel, said members being radially disposed around the barrel, a casingfitting over the limiting portions of the magnetic field members toenclose the solenoids and to serve as a magnetic conductor between thefield members, means fitting over the ends of the barrel to enclose theends of the solenoids, and means for locking `said means in position andalso to clamp the casing between said means to hold the several elementsin a compact unit.

14. An electric tool of the reciprocating motor type comprising 'abarrel or guide, a core member freely movable therein bctweenpredetermined limits, two solenoids axially alined around the barrel.magnetic field members for the respective solenoids to concentrate themagnetic fiux of therespective solenoids atpredetermined regions of thepath of travel of the core, and a casing of magnetizable materialenclosing said coils and their field members and substantially closingthe magneticcircuit of' each of said coils.

15. An electric toolcomprising a reciproeating magnetizablecore, a fieldwinding, a plurality or" groups of laminations spaced circumferentiallyof the axis of movement of the core, and a casing of magnetic mate-'rial enclosing said winding and groups of laminations and forming withsaid laminations a relatively fixed field structure with respect towhich said core'is movable.

16. An electric tool comprising a reciproeating magnetizable core, aplurality of field windings disposed in different positions along thepath of movement of said core, a plurality of circumferentially spacedgroups of outwardly extending laminae in the magnetic circuit of each ofsaid windings, an air gap for each winding between the ends of groups oflaminations approaching each other.longitudinally of' the movement ofsaid core. and an enclosing casing of' magnetic material substantiallyclosing the magnetic circuit between the outer portions of the groupsof' lamine.

17. An electric tool Comprising a, reciproeating magnetizable core, aplurality of field windings, and a plurality of circumferentially spacedgroups of outwardly extending laminas in the magnetic circuit of each ofsaid windings, the adjacent groups of 1aminte for the different windingsbeing separate from each other.

18. An electric tool comprisin a. reci roeating magnetizable core, aplura ity of: eld windings, and a plurality of circumferentially spacedgroups of outwardly extending llamina@ in the magnetic circuit of eachof said windings, the adjacent laminas of the different windings beingspaced from each other llongitudinally of the movement of said core.

(fg/"19. An electric tool comprising a reciproeating magnetizable core,a plurality of field windings, a plurality of circumferentially spacedgroups of outwardly extending laminae in the magnetic circuit of each ofsaid windings, the adjacent groups of lamin for the different windingsbeing separate from each other, and an enclosing casing of magneticmaterial substantially closing the magnetic circuit of each of saidwindings.

20. A percussive tool of the reciprocatin electric motor type comprisingfront an rear solenoids, a magnetizable core structure actuated by saidsolenoids, laminated field members for concentrating the magnetic fluxesproduced by each solenoid in an air gap within the length of thesolenoid, a yielding back-stop adjacent the air gap of the rearsolenoid,`a tool bushing adjacent the front end of the motor, and a toolshank extending through said bushing and terminating adjacent the airgap ofthe front solenoid, the length of said core structure, the lengthof the air gaps and the distance between the air gaps being such thatthe core structure is not actuated by the rear solenoid when said toolshankjs removed and said core structure engages said bushing.

21. An electric tool comprising a tool shank and a core stop adjacentopposite ends thereof, a plurality of field windings, magnetizable fieldmembers for each winding spaced from each other longitudinally andVapproaching each other longitudinally to form an air gap, and amagnetizable reciproeating core engaging said tool shank and core stopand movable past the positions in which it reduces said air gaps tominimum length.

22. An electric tool comprising a reciproeating magnetizable core.` aplurality of rgroups of circumferentially spaced and outwardly extendinglaminae disposed along the path of said core, a field winding positionedbetween adjacent groups of lamince7 and a easing of magnetizablematerial engaging the radial extensions of said laminae which projectbeyond the outer periphery of said winding.

v 23. `An electric tool comprising a reciproeating magnetizable core, aplurality of groups of cireumferentially spaced and out wardly extendinglaminee disposed along the path of said core, a plurality of axiallyaligned windings, each positioned between adjacent groups of laminae,and a casing of 5 magnetizable material enclosingrsaid Wind; ings andengaging the radial extensions of the outwardly extending lamine whichproject beyond the outer periphery of the windings.

In testimony whereof I hereunto affix my signature this 22nd day ofJuly, 1922.

CARL S. WEYANDT.

